How to be grandmaster?

Just improve your game in general in any way you can. Hire a chess coach, and not just any coach, a chess coach which you feel you connect with. They have the art down of spotting the areas requiring the most attention in your games to help you improve as a player and the patience to help you improve. If you're already improving by means of your own training methods, never know what you may learn by a second set of eyes. If you're serious about your game, go to school for it, hire a professional. Even a prodigy like Magnus Carlsen had his coaching.

1) No one will coach you for free. If you want something then you will have to pay the price.
2) You will never be a GM, let alone become stronger than Carlsen.